created for better rejection. The filter is fabricated using the substrate Rogers 5880 with relative dielectric constant of 2.2, loss tangent d 5 0.0009, and thickness of 0.787 mm. The geo- metric parameters are listed in Table 1. The results have shown that the good properties of low-in-band insertion loss, good out- band rejection, and compact size have been achieved and veri- fied. The discrepancies between the simulation and measurement results are due to fabrication uncertainty. 4. CONCLUSION In this article, a novel dual-band bandpass filter using CRLH triangle mushroom structure and DGS is proposed. The pro- posed filter uses triangle mushroom structure as the CRLH TL to achieve low-in-band insertion loss and compact size, and DGS to achieve out-band rejection. Good properties of low-in- band insertion loss, good out-band rejection, and compact size have been achieved and verified. In real application, it is easy to redesign the filter by tuning the passbands separately to meet new specifications. The proposed filter is fabricated without complex fabrication process. It is proved that CRLH structure and DGS can be both used to reduce the size of the filter and increase the rejection between the passbands in mul- tipassband filter applications for the first time. This new com- bination of the two different structures has succeeded in achieving excellent performance. This novel filter can be applied in the microwave circuits and wireless communication systems. ACKNOWLEDGEMENT This work is supported by National Natural Science Foundation of China (Grant No. 61201004) and the Fundamental Research Funds for the Central Universities (ZYGX2011J011). REFERENCES 1. V. Veselago, The electrodynamics of substances with simultaneously negative values of e and l, Sov Phys Usp 10 (1968), 509–514. 2. M. Studniberg and G. V. Eleftheriades, A quad-band bandpass filter using negative-refractive-index transmission-line (NRI-TL) metama- terials, In: Proc IEEE Atennas Propag Soc Int Symp, Honolulu, HI, 2007, pp. 4961–4964. 3. J.-Y. Lee, D.-J. Kim, and J.-H. Lee, High order bandpass filter using the first negative resonant mode of composite right/left-handed trans- mission line, Microwave Opt Technol Lett 51 (2009), 1182–1185. 4. M.-R.-M. Hashemi and T. Itoh, Dual-band composite right/left- handed metamaterial concept, IEEE Microwave Wirel Compon Lett 22 (2012), 248–250. 5. F. Bongard, J.-P. Carrier, and J.-R. Mosig, Enhanced CRLH Trans- mission line performances using a lattice network unit cell, IEEE Microwave Wirel Compon Lett 19 (2009), 431–433. 6. A.-M.-E. Safwat, Microstrip coupled line composite right/left-handed unit cell, IEEE Microwave Wirel Compon Lett 19 (2009), 434–436. 7. T.-K. Kataria, S.-P. Sun, A.-C. Chavez, and T. Itoh, New approach to hybrid multiplexer using composite right-left handed lines, IEEE Microwave Wirel Compon Lett 21 (2011), 580–582. 8. V. Radisic, Y. Qian, R. Coccioli, and T. Itoh, Novel 2-D photonic bandgap structure for microstrip lines, IEEE Microwave Guided Wave Lett 8 (1998), 69–71. 9. S.-W. Zhao, Z.-X. Tang, Y.-W. Wu, and L.-F. Bao, Linearity improved doherty power amplifier using coupled-lines and a capaci- tive load, IEEE Microwave Wirel Compon Lett 21 (2011), 221–223. V C 2013 Wiley Periodicals, Inc. APERTURE COUPLED BaTiO 3 BASED DIELECTRIC RESONATOR ANTENNA WITH DUAL-BAND Elder E. C. Oliveira, 1 Adaildo Gomes D’Assunc ¸ ~ ao, 2 Joao B. L. Oliveira, 3 Alciney M. Cabral, 3 Pedro C. Assis Jr., 1 and Marcelo S. Vieira 1 1 Department of Communication Engineering, State University of Par- a  ıba (UEPB), CEP , 58706-560, Patos, PB, Brazil 2 Department of Communication Engineering, Federal University of Rio Grande do Norte (UFRN), Caixa Postal 1655, CEP , 59078-970, Natal, RN, Brazil; Corresponding author: adaildo@ct.ufrn.br 3 Institute of Chemistry, Federal University of Rio Grande do Norte (UFRN), CEP, 59078-970, Natal, RN, Brazil Received 30 March 2013 ABSTRACT: A low profile and dual band rectangular dielectric resona- tor antenna (DRA) based on high permittivity BaTiO 3 is proposed. The antenna main characteristics are investigated for wireless communication system applications at the frequency band from 6.0 to 8.0 GHz. The antenna design is performed using Ansoft HFSS through the finite element method. Antenna prototypes are built and measured on a vector network analyzer (R&S ZVB14 model) for comparison purpose. Agreement between simulated and measured results is observed. V C 2013 Wiley Peri- odicals, Inc. Microwave Opt Technol Lett 55:2759–2763, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27939 Key words: oxide mix; ceramic powder; DR; DRA antenna 1. INTRODUCTION Lately, a growing interest has been observed to bring different telecommunication services together into a single compact hand- set unit with high-quality performance. In this context, an antenna with reduced dimensions and able to operate at various frequen- cies is required. Dielectric resonators (DR) with predefined for- mats and composed of high-permittivity (e r > 10) materials (such as ceramics) are compact and solid structures, which able to reso- nate at microwave band [1–4]. Therefore, attractive features such as high dielectric constant and low losses associated with the absence of surface waves make these resonators very attractive for antenna designs and applications [5]. Additionally, several ceramic materials exhibit these properties and are suitable for antenna applications, among which stands out the titanate-based compounds. In this work, a ceramic tablet with low profile and rectangular cross section based on barium and titanium oxides (BaO/TiO 2 ) is designed and fabricated using a conventional Figure 1 X-ray diffractogram of BaTiO3 DOI 10.1002/mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 55, No. 11, November 2013 2759